烟台市夹河段海水入侵与时空演化研究

烟台市夹河下游河谷地区是海水入侵的最严重区域。传统上采用的单一指标(Cl—浓度分级)对海水入侵程度进行评价具有一定的局限性。论文运用模糊数学的基本思想方法,根据烟台市夹河近河口地区地下水水质受海水侵染的特点,并基于咸、淡水中的重要特征成分的显著差异,选取了Cl-、M、SO42-r、HCO3/rCl及SAR五项化学特征指标作为模糊综合评判海水入侵程度的评价指标。将模糊数学最大隶属度原则应用到海水入侵地下水水质评价中。建立了模糊数学模型。对海侵区中具典型意义的11个监测井点分3个年份(1994,1999及2004年)的海水入侵程度分别进行了评价。评价结果认为烟台市海水入侵主体规模在1994年就已基本形成,由套子湾沿岸向内延伸,在套子湾沿岸呈带状分布,向内宽度逐渐减小。严重浸染区集中在该区滨海平原沿海一带,沿海岸呈带状分布。评价结果较客观地反映了夹河近河口地区海水入侵的时空演化特点。

Evaluation and development trend of seawater intrusion in the middle and lower reach of Jiahe River, Yantai City, Shandong Province

The valley area of lower reaches of Jia he River is the most seriously intruded by seawater in Yantai City.Adopting traditional single index(Cl~-concentration classify) has some limitation for evaluating the degree of seawater intrusion.Comparing to this method,a mathematical fuzzy method is used in this paper.According to the characteristic of the groundwater quality intruded by seawater in the reaches of Jiahe River and the remarkable difference of characteristic ingredient between saltwater and freshwater,five indexes including Cl~-,M,SO~(2-)_4,rHCO_3/rCl and SAR are adopted to comprehensively evaluate the intrusive degree of groundwater.Maximal subordinated degree principal of fuzzy mathematics is used to evaluate the groundwater quality,and then fuzzy mathematics model is established.And the seawater intrusive degree of 11 typical monitoring points is evaluated in the three different years(1994,1999 and 2004).The results of evaluation indicate that primary zone of seawater intrusion is formed in 1990.It extends inwardly and shows zonal distribution along coast of Taozi Bay.The width of the zone is gradually declined inwardly.And the serious intrusion zone is centralized in the areas of strand plain and shows zonal distribution along coast.Evaluative result objectively reveals the temporal-spatial evolution characteristics of seawater intrusion of Jiahe River area in Yantai City.